textproduct: Quad Cities

KEY MESSAGES

- Heat and humidity returns this weekend and into early next week. Heat indices around or exceeding 100 degrees are expected Sunday and Monday. An Extreme Heat Watch has been issued for Sunday into Monday.

- Thunderstorms are possible Sunday and Monday that may be strong to severe.

SHORT TERM /THROUGH TONIGHT/

Issued at 129 AM CDT Fri Jul 24 2026

Forcing aloft will bring a band of sprinkles and showers through the central parts of the area through mid-day. Progged soundings of the atmosphere continue to show respectable amounts of dry air. The combination of the dry air and weakening forcing will result in a gradual decay of the light precipitation through the morning.

Tonight return flow develops which will cause dew points to slowly rise through the night. Another passing upper level disturbance in the warm advection aloft may generate some isolated to low end scattered (10-30%) showers during the night. A rogue thunderstorm cannot be ruled out.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 129 AM CDT Fri Jul 24 2026

Saturday through Monday Assessment...a certainty (>98%) of high heat and humidity. Low (<20%) confidence regarding possible storms

Heat and humidity will surge into the area as the heat dome builds north into the Plains. Taking into account the warm and moist bias of the model consensus, dew points will slowly climb through the 60s on Saturday with low and mid 70s dew points Sunday and Monday. With progged temperatures eventually reaching 90 to 95 Sunday/Monday, heat indices at or exceeding 100 are expected Sunday into Monday.

The wild card in all this will be the organized nocturnal storms moving around the edge of the heat dome. The activity will move across Minnesota into Wisconsin and eventually turn south toward Illinois. When/where they turn south will be the key to whether or not parts of the area get side-swiped by the storm complexes and potential diurnal development in the afternoon. We'll be dealing with non-linear processes which are not handled well by the models. Storm development Friday night into Saturday will influence the development of storms the following night et cetera.

Thus while the potential for storms is low, if storms occur the impacts could be significant; one is strong to severe storms, the other is potentially much lower temperatures for parts of the area Sunday and Monday.

Given this we will be hoisting an excessive heat watch for areas along and west of the Mississippi and west central Illinois. These headlines may or may not need to be expanded further east of the Mississippi.

Monday night through Thursday Assessment...high (>80%) confidence of continued heat and humidity

Starting Monday night and continuing the remainder of the week, the heat dome and associated upper level ridge slowly de-amplifies. A weak surface high will briefly turn winds around to the north and east Monday night through Wednesday that will slightly lower temperatures. However, heat indices in the mid and upper 90s will still be common.

Wednesday night into Thursday the various models bring a very weak disturbance through the area. Given the weak forcing this disturbance may or may not produce some convection. Several model solutions are dry but some of their ensemble members generate some light QPF. Thus while the model consensus has a 20 percent chance of rain, most of the area will remain dry.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 610 AM CDT Fri Jul 24 2026

A passing short wave aloft dropping in behind exiting high pressure will continue to produce mainly mid and high level clouds as well as some spotty sprinkles and isolated light showers acrs the area through late morning. Southeast to Southerly return flow slowly develops this afternoon and continues into tonight. Tonight, increasing warm air advection aloft may result in some more isolated to wdly sctrd light showers and sprinkles acrs the area into Saturday morning. CIGs should be mainly VFR, but several CAMs are trying to bring up enough lower moisture to allow for some MVFR stratocu to develop acrs portions of the area especially after midnight tonight.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Extreme Heat Watch from Sunday afternoon through Monday evening for IAZ040>042-051>054-063>068-076>078-087>089- 098-099. IL...Extreme Heat Watch from Sunday afternoon through Monday evening for ILZ015-024>026-034-035. MO...Extreme Heat Watch from Sunday afternoon through Monday evening for MOZ009-010.